i#893: Rtl Heap API replacement, part 4: + free lists per arena + arena header var-size to inline free lists in   main arena per Heap
i#893: Rtl Heap API replacement, part 4:
+ free lists per arena
+ arena header var-size to inline free lists in
  main arena per Heap

git-svn-id: fe3cd4388a6e5a968b09397a3d721fe124e8117a@861 5b54908e-ead4-fc18-b48a-0285e6dbc711

rnk/drmemory,rnk/drmemory,rnk/drmemory,rnk/drmemory